On Sat, 6 Sep 2008 21:11:41 +0200, Markus wrote:
Fourth: America and part of Japan felt, it was cool to chooseThe US and Canada had pretty much settled on 25 Hz and 60 Hz as
defacto "standards", based on Telsa's original work on AC power
reticulation systems, before Siemens decided that 50 Hz should be the
de facto European "standard".
The issue with AC power in its early technology stages was that the
frequencies that were best for electro-motive purposes (factories and
railways etc) were generally poor for general electro-illumination
purposes, and vice versa.
Tesla determined through some practical experiments that 60 Hz was
minimum AC frequency that is suitable for general incandescent lamp
illumination applications, without getting noticeable "flickering".
Siemens later determined that 50Hz produced acceptable results with
the incandescent lamps they were able to manufacture in Europe.
The most popular US rail electrification frequency of 25 Hz was an
attempt to trade off electro-motive and electro-illumination needs but
was never really satisfactory for either purpose.... though it was not
until the second half of the 20th century that 60 Hz frequency
displaced 25 Hz for domestic power reticulation in the some regions of
North Eastern parts of North America, and not until circa 2005/6 that
25 Hz power generation in North America finally ceased altogether.
Frequencies around 15Hz were found to be good for rail electrification
purposes given the early AC motors. 15 Hz was used in a few places in
the US and 16.66 Hz over wide areas of Europe. The 15 Hz US
installations never went on to gain critical mass.... the Southern
Pacific railroad did at one stage give serious though to adopting it
for mainline electrification purposes and did electrify a branch line
(interurban) using 15 Hz power as an experiment with 15 Hz power,
which managed to hang on to circa 1943.